This collet clamping nut is made of , which can withstand use. Features the chromium steel material, which has high durability, not easy to deform. Fine workmanship, practicality. This collet clamping nut will make the repair and fix easier and smoother. Features -Color: Black -Material: chromium steel -Size: 1.80X1.80X1.30cm/0.71X0.71X0.51in Inner thread: 14mm Nut pitch: M14x0.75 External diameter: 19mm Suitable collet: 11-A Suitable wrench: 17mm - Made of chromium steel, it is strong and , not easy to break. collet clamping nuts have balancing holes to prevent wear and noise. - High accuracy and concentricity, prolong the service life of the spindle and reduce the breakage rate of the drill bit. - It is suitable for ER-type tool holders, tool bars, extension rod nuts to hold drills, boring tools and other tools. - workmanship, reasonable structure, professional and practical, can bring you convenience. Package list: 4 x clamping nuts